Oil may be pumped throughout an engine to lubricate engine components. In addition, oil may be used in the engine as a motive power medium to actuate various devices within the engine. For example, an engine may include valve operators that may be selectively deactivated by supplying pressurized oil to the valve operators. The same engine may also include piston cooling jets that spray oil on engine pistons to cool the engine pistons. A variable displacement oil pump may pump oil throughout the engine and oil pump output pressure may be increased via increasing a displacement of the oil pump. However, if the oil pump is operated at too high of a pressure, engine fuel consumption may degrade. Conversely, if the oil pump is operated at too low of a pressure, the engine may not be sufficiently lubricated or devices within the engine may not operate as is expected. Therefore, it would be desirable to provide a way of controlling oil pump pressure such that devices supplied oil by the oil pump operate as desired and engine fuel consumption is low given the requirements of devices receiving oil from the oil pump.
The inventors herein have recognized the above-mentioned disadvantages and have developed a method for operating an engine, comprising: receiving engine operating conditions to a controller; and adjusting a displacement of an engine oil pump via a controller in response to a maximum value of a plurality of minimum oil gallery pressures to operate a plurality of engine oil consumers.
By adjusting a displacement of an oil pump in response to a maximum value of a plurality of minimum oil gallery pressures to operate a plurality of engine oil consumers, it may be possible to provide the technical result of supplying oil sufficient to operate and lubricate a plurality of devices while lowering engine fuel consumption. Specifically, if engine cooing jets operate properly at a minimum pressure of 200 kPa and engine valve operators operate properly at a minimum pressure of 220 kPa, the oil pump displacement may be adjusted to provide 220 kPa in the oil galleries leading from the oil pump to the oil consumers. As a result, all the engine oil consumers may operate as desired. On the other hand, if the engine valve operators are not requested to be deactivated, the oil pump displacement may be adjusted to provide 200 kPa in the oil galleries leading to oil consumers. In this way, oil pump pressure may be adjusted to operate oil consumers and reduce engine fuel consumption.
The present description may provide several advantages. In particular, the approach may reduce engine fuel consumption. Further, the approach may provide sufficient oil pressure throughout the engine to engine oil consumers. Further still, the approach may improve reliability of the engine oil pump by matching oil pump output to oil pump demand.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.